1. Field of The Invention
This invention relates to novel compounds which prevent or block a Factor VIIa (FVIIa ) mediated or associated process or event such as the catalytic conversion of Factor X (FX) to Factor Xa (FXa ), Factor VII (FVII) to FVIIa or Factor IX (FIX) to Factor IXa (FIXa ). In particular aspects, the compounds of the invention bind FVIIa or its zymogen FVII. The invention also relates to pharmaceutical compositions comprising the novel compounds as well as their use in research, diagnostic, therapeutic, and prophylactic methods.
2. Description of Related Disclosures
The tissue factor-Factor VIIa (TF-FVIIa ) complex constitutes the primary initiator of the extrinsic pathway of blood coagulation (Carson, S. D., and Brozna, J. P., Blood Coag. Fibrinol. 4:281–292 (1993); Davie, E. W., et al., Biochemistry 30:10363–10370 (1991); Rapaport, S. I., and Rao, L. V. M., Arterioscler. Thromb. 12:1111–1121 (1992); Davie, E. W., Thromb. Haemost. 74: 1–6 (1995); Rapaport, S. I. and Rao, L. V. M., Thromb. Haemost. 74: 7–17 (1995); Mann, K. G., Thromb. Haemost. 82: 165–174 (1999); Edgington, T. S. et al., Thromb. Haemost. 78: 401–408 (1997)). The complex initiates the extrinsic pathway by activation of FX to FXa , FIX to FIXa , and additional FVII to FVIIa. The action of TF-FVIIa leads ultimately to the conversion of prothrombin to thrombin, which carries out many biological functions (Badimon, L., et al., Trends Cardiovasc. Med. 1:261–267 (1991)). Among the functions of thrombin is the conversion of fibrinogen to fibrin, which polymerizes to form a clot. The TF-FVIIa complex also participates as a secondary factor in extending the physiological effects of the contact activation system.
The involvement of these plasma protease systems has been suggested to play a significant role in a variety of clinical manifestations including arterial and venous thrombosis, septic shock, adult respiratory distress syndrome (ARDS), disseminated intravascular coagulation (DIC) and various other disease states (Haskel, E. J., et al., Circulation 84:821–827 (1991)); Holst, J., et al., Haemostasis 23(suppl. 1): 112–117 (1993); Creasey, A. A., et al., J. Clin. Invest. 91:2850–2860 (1993); see also, Colman, R. W., N. Engl. J. Med. 320:1207–1209 (1989); Bone, R. C., Arch. Intern. Med. 152:1381–1389 (1992) Presta, L. G. et al., Thromb. Haemost. 85: 379–389 (2001)).
Antibodies reactive with the protease domain of FVII have been shown to inhibit TF-FVIIa proteolytic function (Dickinson et al., J. Mol. Biol. 277:959–971 (1998)). Peptides corresponding to the EGF2 domain of FVII are potent inhibitors of TF-FVIIa mediated activation of FX (Husbyn et al., J. Peptide Res. 50:475–482 (1997); Presta supra). Several peptides corresponding to various regions of FVII (for example, amino acid sequence residues 372–337 and 103–112 of hFVII) have been proposed as therapeutic anticoagulants based upon their ability to inhibit TF-FVIIa mediated coagulation (International Publication No. WO 90/03390; International Publication No. W095/00541). Active site modified FVII variants capable of binding tissue factor (TF) have been proposed as pharmaceutical compositions for the prevention of TF/FVIIa mediated coagulation (International Publication No. WO 91/11514). U.S. Pat. Nos. 5,759,954, 5,863,893, 5,880,256 and 5,834,244 describe variant Kunitz-type serine protease inhibitors that inhibit TF-FVIIa activity and have been shown to prolong tissue factor initiated prothrombin time (PT). This is consistant with the ability of these TF-FVIIa active site inhibitors to prevent FX activation through inhibition of the TF-FVIIa complex.
The architecture of the active site of the serine proteases involved in the coagulation cascade is very similar. Although nonselective with respect to small chromogenic substrates, the proteases exhibit a strong specificity for their natural macromolecular substrates. Exosites on these enzymes play an important role in substrate recognition and specific cleavage. Blocking such interactions could result in the specific inhibition of a single protease in the coagulation pathway.
Two classes of peptide exosite inhibitors of human FVIIa have been identified (International Publication Number WO 01/10892; International Publication Number WO 01/01749; Dennis, M. S., et al. (2000) Nature, 404: 465–470; Dennis, M. S., et al. (2001) Biochemistry, 40: 9513–9521; Roberge, M., et al. (2001) Biochemistry, 40: 9522–9531). The two peptides classes are typified by peptides designated E-76 (TF76; SEQ ID NO: 8, International Publication Number WO 01/01749) and A-183 (TF183; SEQ ID NO: 23, International Publication Number WO 01/10892), which bind to two distinct exosites on the protease domain of FVIIa and inhibit the activation of FX to FXa by TF-FVIIa with IC50 values in the nanomolar range. Similar potency was observed for the inhibition of the amidolytic activity of TF-FVIIa using the peptides. Although these peptides are potent inhibitors of TF-FVIIa activity, they do not completely inhibit the enzymatic activity of FVIIa. At saturating concentrations of peptide, E-76 and A-183 show a maximal inhibition of FX activation of 90% and 78%, respectively, whereas maximal extent of inhibition of the amidolytic activity was 50% and 32%, respectively.